1. Field of the Invention
This invention relates to grease boxes comprising a galvanic gas-generating element for delivering automatically a lubricant. More particularly this invention relates to an improved galvanic element in a grease box containing a galvanic gas-generating element which automatically delivers lubricant over a long period of time to a lubricating location.
2. Discussion of the Prior Art
Lubricators which automatically deliver lubricants have been known. Such are described in German Pat. No. 1,256,001, U.S. Pat. No. 3,430,731 and U.S. Pat. No. 3,842,939, the disclosures of which are hereby incorporated herein by reference. In the lubricator of U.S. Pat. No. 3,430,731, for example, there is provided a device which is brought into operation at a desired instant by the generation of gas in a tightly closed hollow extensible body. Within the extensible body pressure develops which causes the walls of the extensible body to increasingly bear against a lubricant maintained in a lubricant chamber. The lubricant is, in turn, caused to flow through a lubricant channel from the lubricator on to a lubricating location. By the use of such a device gas can develop in the hollow extensible body over a period of time. This, in turn, causes the lubricant to be dispensed to the lubricating location over the same period of time. The device is useful in the lubrication of various bearing surfaces and the like over a long period of time on the order of months.
Unfortunately, it has been found that the amount of lubricant which is dispensed to the bearing surface oftentimes varies. It is thought that the gas which is generated in the galvanic element may be generated at an inconstant value. The gas is usually generated by disposing the galvanic element which comprises a positive electrode current conductingly connected to the negative electrode into the electrolyte by engagement of a screw from a space closed off from the extensible body. Since during the generation of gas the negative electrode's surface is altered the relationship of the positive electrode's surface to the negative electrode's surface changes. When this change occurs it is theorized that the amount of gas which is generated varies which, in turn, effects the amount of pressure generated in the hollow extensible body. Since the pressure varies over the period of time the amount of lubricant which is dispensed to the lubricating locating correspondingly varies. It has therefore become desirable to provide an improved galvanic gas generating element wherein the effective surface of the positive and negative electrodes are maintained constant so as to generate constantly the same amount of gas at the same pressure and to cause the same amount of lubricant to be dispensed over the period of time. It has further become desirable to provide such a gas generating galvanic element which will dispense an exact constant amount of lubricant over several months.